Interpretive Summary: Fruits of Ziziphus mauritiana L. (ber) are consumed in fresh and dried/processed forms in many countries across Asia including Pakistan. In the present study, nine phenolic acids (protocatechuic, p-hydroxybenzoic, ferulic, chlorogenic, vanillic, caffeic, vanillin, o- and p-coumaric acids) were identified and quantified using ultraviolet and mass spectral detection and external calibration with commercially available standards. It was found that p-coumaric acid (3719 ± 22 µg/g) was the predominant phenolic acid extracted from ber samples. The results presented in this study indicate that Ziziphus mauritiana (ber) is a good natural source of phenolic acids and that pressurized liquid base hydrolysis extraction (PLBHE) using Dionium Cell can be used for the assay of phenolic acids.